Outlet-box.



w. A. HALL. OUTLET BOX.

APPLICATION FILED APB.2'7, 1912.

Patented Mar-. 16, 1915.

' WiTNESSES: J fay:

INVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

wiLLiAm A. HALL, OF NEW You, 1v. Y., nssrenoa T rnomns &, IBET'IS comrm, or

NEW YORK, N. Y., A CORPORATION OF NEW YORK.

OUTLET-BOX.

Specification of Letters Patent.

Patented Mar. 16, 1915.

' To all whom it may camera.

Be it known that 1, WILLIAM A. HALL, a

citizen of theUnited States, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Outlet-Boxes, of which the following is a specification.

This invention relates to outlet-boxes of the type commonly employed in installing electric wiring in buildings.

' More particularly, the invention relates to boxes of this type known-as knock-out boxes, the walls of which are so formed as to permit of readily removing a disk or other shaped section of the wall so as to provide an opening leading to the interiorof the box through which the end of a conductor may be inserted.

The invention is directed to the provls on of an improvedform of outlet-box havln knock-outs: provided in the wall thereo which may be readily removed and so constructed that the wall of the box is watertight notwithstanding the provision for knock-outs in the wall.

On account of the manner in which outlet-boxes are employed, the locations in which they are mountedand the fact that the boxes inclose exposed parts carrying electric current, it is highly important that the walls of such outlet-boxes be watertight. At the same time it is important that knock outs be provided in the walls of such outletboxes so that as many conductors as are desired may be led into the box at various points around the wall of the box. It has heretofore been proposed to make these knock-out outlet-boxes from cast metal and to provide circular depressions in the walls of a box defining the knock outs, the material at the bottom of each of these depressions being so thin that it may be readily ruptured in order to remove the lmock-out and thus provide an opening. This construction, however, has always been objectionable because of the fact that the .removal of the kI1OCk'rOl1t' from a cast metalbox leaves a rough edge of metal around the opening which interferes with properly joining the o tlet-box and conduit, and furthermore, p rmits moisture to enter. Outlet-boxes have i also been made of sheetmetal, the knock-outs being provided by cutting disks of metal from the walls of the boxes andwedging or otherwise holding these disks 'in their openings. With this construction, an opening may be readily provided by striking a blow upon a disk and thus forcing it out of its opening. Knock-out boxes so constructed, however, are open to the objection that they are not watertight. The cutting of the metal of the wall of the box all the way through provides a. narow space into which moisture may enter and corrode the metal of the box-wall and knock-out disk at the junction between them. This invention is directed to the provision of an improved form of knock-out outlet-box, either of sheet-metal or castmetal, wherein the junction between the boxwall and knock-out disk is watertight. In accordance with the invention a filling is provided about the edges ofv the knock-outs and between those edges and the walls of the openings in which the knock-outs lie, which fills the spaces so as to make the joints at these points so tight as to preclude the entrance of moisture into the interior of the box through the joints about the knockouts.

The invention is illustrated in the accompanying drawings in whic Figure 1 is a perspective view of a sheetmetal outlet-box and Figs. 2 to 6 are sectional views through a wall of the box illustrating methods which may be employed in the construction of the knock-outs.

Referring first to Fig. 1, an outlet-box is shown in this drawing made fromsheetmetal, preferably by forming the bottom and the four sides of the box from a single pieceof sheet-metal. The walls of the box are provided with knock-outs in the usual or any suitable manner. In the present instance, the knock-outs are shown as cut from the walls of the box by a stamping operation so that the knock-out is entirely severed from the wall and thereafter each lmock-out is forced back into its opening in the wall of the box so as to become wedged therein. It will be understood, however, that the knockouts may be otherwise formed without departing from the spirit of my invention, as for instance, by cutting each disk from the wall of the box around a large portion but less than the whole of the periphery of the disk.

Referring now to Fig. 2, a wall of the box is shown at 10 having provision for two knock-outs 11 and 12 therein. A disk is cut from the wall 10 of the box so as to become entirely disconnected therefrom. This same disk may be again inserted in the opening thus formed to provide a removable closure for the opening. Preferably, how.-

ever, a disk of thinner metal is employed for closing the opening in the wall 10. Such a disk is shown at 11. When inserting this and 13 are subjected to pressure tending to force them together, as a result of which the soft metal 13 is forced into the space between the peripheral surface of disk 11 and the edge of the opening in wall 10. The

application of the pressure is preferably such as to cause the disk 11 to become flush with one side of the wall 10 and the soft metal 13 tobecome flush with the other side of that wall. The ositions of the parts, a er being subjected to pressure thus, are shown at the right of Fig. 2 wherein it will be seen that the exposed face of the diskis flush with one side of the wall 10 and the soft metal 13 has been forced into the space between the tapered peripheral" surface of disk 12 and the edge of the opening in wall 10, as shown at 15. When the parts have been forced into the position shown at the right of Fig. 2, the knock-out will be held tightly in its opening in wall 10 but may be readily removed therefrom by striking it lightly but moisture will not enter the box through the joint about the disk 12 because of the provision of the filling 15 of soft metal.

Fig. 3 illustrates a construction which may be employed in making a cast-metal "knock-out outlet-"box which Is waterproof. The construction shown in this fi re is the same as that shown-in Fig. 2 except thatthe opening through the wall 10 is of smaller diameter at one end than at the other so that a ledge 16 is provided within ing. In assembling the parts, a disk .1 of soft metal of a diameter corresponding to the diameter ofthe larger portion of the opening in wall 10 is placedin that opening against the ledge 16 and the smaller end of the diskll is then inserted in the opening and moved into contact with disk 17 These parts are then subjected to pressure which forces the disk 11 inwardly so that its outer face becomes flush with the facefof wall 10 and so that'the soft metal 17 is compelled to fill in the space between-the peri heral surface of disk 11 and the wall of t e opening, as shown at 18, theparts being then m' the the 0 enthrough, and a led e positions illustrated at the right of Fig. 3.

Fig. 4 illustrates aconstruction similar in all respects to that shown in Fig. 3 except that a ring or, annulus 19 of the soft metal iBs em3ployed instead of the disk 17 shown in 1g. Fig. 5 illustrates another construction which may be employed in accordance with which a circumferential groove is provided in the wall ofthe opening provided forthe reception of the knockout disk 11. This groove is shown at 20.. The disk 11 and the disk 21 of soft metal after being assembled as shown at the left of Fig. 5, are subjected to pressure which forces the disk 11 inwardly. As this occurs, the soft metal 21 is forced into the groove 20 as shown at 22 so as to make the joint between the disk and the wall'of the box watertight.

In Fig. 6, the opening in the wall of the box is countersunk at one end, as shown at 23. The knock-out 11 a nd the disk 21 of soft metal are assembled" as before and subjected to pressure whereupon the soft metal is forced into the countersink 23, as shown at 24:.

In all of the constructions herein shown and described either cast-metal or sheetmetal may be emplo ed and the advantages incident to the use 0 botlnor either retained, these including the provision of an opening having a smooth surface on the removal of the knock-out. In each case, however, the

joint between the knock-out and the wall of the opening in which it lies is a watertight joint by reason of the provision of a filling of soft metal or othersuitable substance in this joint.

It will be understood that the invention herein described is applicable to various forms of boxes of the general type of that myself limited in any way as to the type of box in which this invention is employed.

Having described my I invention, what I claima's new therein and desire to secure by Letters Patent'of the United, States is;

I 1.;A. metallicoutlet-box having one side thereof provided with an 'opemng thereinthe wall of said opening, a filling o compresible, non-absorbent' material restin'g'u on said ledge and extending around. the we s ofsaid opening as a-lining' therefor, between said ledge and a face of the side of the box, and a knockout disk having a tapered periphery seated in on said filling with its p6 riphery we ge tact with the edge portions of said fillin the outer face of sa1d disk being flush wit the said face of the side of the box, substantially as set forth. 7

2. A metallic outlet-box having one side thereof provided with an opemng there'- through, and aledge in the wall of said.

opemng, a filling o compressible, non-absorbent material comprising a disk-like base I portion resting upon said ledge and an edge portion extending said base portion around the'walls of said opening as a lining therefor, between said ledge and a face of the side of the box, and

a tapered knockout disk seated in said. opening upon the base portion of the filling and with its edges wedged into close water-tight contact with the edge-portion (of the filling, substantially as set forth. I

3. A metallic outlet-box having one side through, a fillin wa o sai openingasa from the periphery ofthereof provided with an opening theresorbent material comprising a base portion of slight thickness extending across the opening, between the two faces of the said side of the box, and an edge-portionextending from" the ri her of said base ortion around the fining therefor, between the base portion and one face of the side of thebox, and a tapered knockout di sk seated tion of the filling and into close water-tight contact portions of the filling, forth.

with its edges we with-the edge g of compressible, non'-ab-- in said opening upon the base (porged substantially as .set

This specification signed and this 25 day of April, 1912. I

WILLIAM A. it v;- Witnesses:

PETER S. OHARA, LEwIs MILTON. 

